Relay

ABSTRACT

A single pole double throw relay having two stationary contacts and a movable contact spring biased against the first stationary contact. A free floating armature carries an adjustable finger which, when the energized coil pulls the armature against the core, pushes against the biasing spring to move the movable contact into contact with the second stationary contact. During manufacture, the second stationary contact can be moved by an adjusting screw to set the air gap, and the adjustable finger can be adjusted to set spring over-travel.

United States Patent Heath July 24, 1973 [54] RELAY 1,429,009 9/1922 Wynne 335/98 [75] Inventor: Thomas C. Heath, Anderson, Ind.

Primary Examiner-Harold Broome Asslgnee? S 39 col'lmratlolls Attorney--Paul Fitzpatrick et al.

etroit, 1c

[22] Filed: Sept. 5, 1972 57 A S [21] Appl. No.: 286,310 A single pole double throw relay having two stationary contacts and a movable contact spring biased against the first stationary contact. A free floating armature (gill. carries an adjustable finger which, when the energized [58] Fieid 132 187 coil pulls the armature against the core, pushes against the biasing spring to move the movable contact into contact with the second stationary contact. During [56] References Cited manufacture, the second stationary contact can be moved by an adjusting screw to set the air gap, and the UNITED STATES PATENTS adjustable finger can be adjusted to set spring over- 3,184,564 5/1965 Ryckman et al 335/187 l. 3,165,607 1/1965 Hogan 335/187 3,624,571 11/1971 Magida 335/197 2 Claims, 3 Drawing Figures RELAY SUMMARY OF THE INVENTION In the manufacture of relays, the spatial positioning of the fixed and moving contacts must be accomplished with great accuracy to insure the correct and reliable operation of the relays produced. A small massproduced relay cannot be economically manufactured to the narrow tolerances required for reliable operation unless suitable adjustments are made to the relay after assembly. Such adjustments are generally performed by hand.

My invention, however, is a relay constructed in such a manner as to allow precise adjustment of the contacts by machine, thus saving expensive labor. Even if the manufacturer elects to have the adjustments made by hand, they can be made with great precision; and the reliability of the relays is thereby increased.

Further objects and advantages of my invention will appear in the accompanying description and drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cutaway view of the preferred embodiment of my invention.

FIG. 2 is a view along line 2-2 in FIG. 1. FIG. 3 is a view along line 3-3 in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures, a general E-shaped core 2 is disposedas shown in a case member 4 made of plastic or another synthetic material. An energizing coil 6 is wound around the center leg of the E-shaped core 2; the two ends of the coil 6 are wire-wrapped around terminals 8 and 10, which project through the plastic case member 4 in which they are embedded.

There are three additional terminals l2, l4 and 16 embedded in and projecting through the case member 4 asshown. Terminal 12 carries a contact 18 on a short rigid arm 20. Terminal 14 carries a contact 22 on the end of a short spring arm 24. The spring arm 24 biases the contact 22 away from the contact 18 but it can be forced toward contact 18 by an adjusting screw 26 which is threadably mounted in the case member 4. A contact 28 is positioned between contacts 18 and 22 on the end of a long spring arm 30 which is attached to terminal 16. The long spring arm 30 biases the contact 28 firmly against the contact 18; but a force of sufficient magnitude on the spring 30 in the direction of contact 22 will move the contact 28 out of contact with contact 18 and into engagement with the contact 22.

on the other side of the E-shaped core from the contacts, a free-floating armature 32 is free to move to or from the E-shaped core within a chamber 34 formed in the other case member 5. n the armature 32 is threadably mounted an adjustable finger 36, which extends between two legs of the E-shaped core toward the long spring arm 30.

During manufacture, after the relay components have been assembled in the case member 4 but before case member '5 is added, the critical adjustments can be made to the relay. First, an ohmmeter or equivalent device is connected between terminal 12 and terminal '14. The adjusting screw 26 is screwed into the case member- 4 until the ohmmeter shows zero resistance, which indicates engagement of the contacts 22, 28 and 18. The inward motion of the adjusting screw 26 is stopped immediately upon the first indication of zero resistance across the terminals 12 and 14. The adjusting screw 26 is then screwed back out a specific number of turns or fraction thereof to set the gap between the contacts 18 and 22, which are, in operation, the two stationary contacts of the relay.

For the second adjustment, the ohmmeter is connected between terminal 14 and terminal 16; and a 12 volt DC supply is applied to the coil 6 by connection across terminals 8 and 10. During assembly, the adjustable finger 36 has been set well back in the armature 32 so that now, when the armature 32 is pulled against the E-shaped core 2, the adjustable finger 36 does not push the contact 28 against the contact 22. Now, however, the adjustable finger 36 is screwed into the relay until the ohmmeter shows zero resistance, which indicates engagement of contacts 22 and 28. The adjustable finger 36 is then screwed further into the relay for a specific number of turns or fraction thereof to create the specific amount of spring over-travel which will quarantee finn engagement of contacts 22 and 28 when the relay is energized. Upon the completion of this adjustment, the case member 5 is ultrasonically welded to the case member 4 to seal the relay closed.

Although the adjustments described above can be performed by hand, they are ideally suited for automatic performance by a machine. For either of the adjustments, a machine-operated screwdriver .-could advance the threaded member steadily until the closing of the appropriate contacts activated a circuit in the machine to cause the screwdriver to turn the threaded member aspecified number of turns in a specified direction from that point. The adjustment of contact gap and spring over-travel could therefore be made inexpensively and accurately so that an economically competitive relay could be produced.

The preceding description is that of a preferred embodiment and is not to be construed as exclusing other embodiments which are obvious to those skilled in the art.

What is claimed is:

l. A relay comprising:

a case;

an electromagnet in the case;

a first contact in the case;

a second contact in the case, the second contact being movable with respect to the first contact;

first spring means effective to bias the second contact away from the first contact;

first adjustable screw means in the case, the adjustable screw means engaging the first spring means tomove the second contact so as to vary its distance from the first contact;

a third contact in the case, the third contact being movable between the first and second contacts for engagement with either;

second spring means normally effective to bias the third contact into engagement with the first contact;

electromagnetically responsive armature means in the case;

and second adjustable screw means threadably mounted on the armature means, the second adjustable screw means being engagea-ble with the third contact upon energization of the electromagnet to bias the third contact into engagement with the second contact.

2. A relay comprising:

a case made of an insulating material;

an electromagnet in the case;

a first contact fixed in the case;

a first spring arm, one end of which is fixed in the case;

a second contact carried on the other end of the first spring arm, the second contact being normally held separate from the first contact but movable toward the first contact by deformation of the first spring arm;

a second spring arm, one end of which is fixed in the case and the other end of which extends between the first and second contacts;

a third contact carried on the other end of the second spring arm, the third contact being normally biased into engagement with the first contact but movable toward the second contact by deformation of the second spring arm;

first adjusting screw means threadably mounted in the case, the first adjusting screw means engaging the first spring arm to vary the gap between the first and second contacts and being capable of deforming the first spring arm sufficiently to move the second contact into engagement with the third and first contacts;

electromagnetically responsive annature means in the case;

and second adjusting screw means threadably mounted on the armature means for engagement with the second spring arm upon energization of the electromagnet to move the third contact into engagement with the second contact.

*g g 4 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,748,611 Dated July 24, 1973 Inventor(s) I ThOroaS C. Heath is certified 'that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

{- (73) Assignee: "General Electric Corporation" should read General Motors corporatiorifl Signed and sealed this 11th day of June 1974.

(SE AL) Attost: EDWARD nmmrcrmmm. c.' -msmnbflm Atteating Officer Commissioner of Patents J qg gg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated Jul! 24: 1973 Patent No. 3,748,611

Inventofls) Tholnas C. Heath It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

(73) Assignee: "General Electric Corporation" should read I General Motors Corporation Signed and sealed this 11th day of June 19714..

(SEAL) Atteat:

EDWARD H.FLETCHER,JR. c. MARSHALL 1mm Attesting Officer Commissioner of Patents I 

1. A relay comprising: a case; an electromagnet in the case; a first contact in the case; a second contact in the case, the second contact being movable with respect to the first contact; first spring means effective to bias the second contact away from the first contact; first adjustable screw means in the case, the adjustable screw means engaging the first spring means to move the second contact so as to vary its distance from the first contact; a third contact in the case, the third contact being movable between the first and second contacts for engagement with either; second spring means normally effective to bias the third contact into engagement with the first contact; electromagnetically responsive armature means in the case; and second adjustable screw means threadably mounted on the armature means, the second adjustable screw means being engageable with the third contact upon energization of the electromagnet to bias the third contact into engagement with the second contact.
 2. A relay comprising: a case made of an insulating material; an electromagnet in the case; a first contact fixed in the case; a first spring arm, one end of which is fixed in the case; a second contact carried on the other end of the first spring arm, the second contact being normally held separate from the first contact but movable toward the first contact by deformation of the first spring arm; a second spring arm, one end of which is fixed in the case and the other end of which extends between the first and second contacts; a third contact carried on the other end of the second spring arm, the third contact being normally biased into engagement with the first contact but movable toward the second contAct by deformation of the second spring arm; first adjusting screw means threadably mounted in the case, the first adjusting screw means engaging the first spring arm to vary the gap between the first and second contacts and being capable of deforming the first spring arm sufficiently to move the second contact into engagement with the third and first contacts; electromagnetically responsive armature means in the case; and second adjusting screw means threadably mounted on the armature means for engagement with the second spring arm upon energization of the electromagnet to move the third contact into engagement with the second contact. 